accumulate mods from all kbs for keybind processing

src/managers/input/InputManager.hpp

@@ -91,6 +91,9 @@ private:
     STabletTool*    ensureTabletToolPresent(wlr_tablet_tool*);
 
     void            applyConfigToKeyboard(SKeyboard*);
+
+    // for shared mods
+    uint32_t        accumulateModsFromAllKBs();
 };
 
 inline std::unique_ptr<CInputManager> g_pInputManager;